Txhua yam ua tsis tiav ntawm qee kis, thiab hluav taws xob tsis muaj qhov tshwj xeeb. Kev tsim cov tshuab uas cia siab tias peb qhov tseem ceeb ntawm cov khoom siv hluav taws xob tsis ua haujlwm pab txhawb kev ntseeg siab thiab kev pabcuam ntawm cov khoom siv no.
Failure Modes
Muaj ntau yam laj thawj vim li cas cov khoom tsis ua haujlwm. Qee qhov kev ua tsis tiav yog qeeb thiab zoo nkauj, qhov twg muaj sijhawm los txheeb xyuas cov khoom thiab hloov nws ua ntej nws ua tsis tiav, thiab cov khoom siv poob qis. Lwm yam kev ua tsis tiav yog nrawm, ua phem, thiab tsis xav txog, tag nrho cov no tau raug sim rau lub sijhawm kuaj cov khoom pov thawj.
Cov pob khoom tsis ua haujlwm
Lub pob ntawm cov khoom siv muaj ob lub luag haujlwm tseem ceeb: nws tiv thaiv cov khoom tiv thaiv los ntawm ib puag ncig thiab muab txoj hauv kev rau cov khoom sib txuas mus rau hauv Circuit Court. Yog tias qhov thaiv kev tiv thaiv kev tiv thaiv los ntawm ib puag ncig tawg, sab nraud yam xws li av noo thiab oxygen ua rau kev laus ntawm cov khoom thiab ua rau nws ua tsis tau sai.
Kev tsis ua haujlwm ntawm pob khoom tshwm sim los ntawm ntau yam, suav nrog kev ntxhov siab thermal, tshuaj ntxuav tes, thiab lub teeb ultraviolet. Cov laj thawj no tuaj yeem tiv thaiv tau los ntawm kev cia siab tias muaj cov xwm txheej zoo sib xws thiab kho tus qauv tsim kom haum.
Mechanical tsis ua haujlwm tsuas yog ib qho ua rau pob ua tsis tiav. Nyob rau hauv lub pob, qhov tsis xws luag hauv kev tsim khoom tuaj yeem ua rau luv luv, muaj cov tshuaj uas ua rau kev laus sai ntawm cov semiconductor lossis pob, lossis cov kab nrib pleb hauv cov ntsaws ruaj ruaj uas nthuav tawm raws li ib feem mus rau hauv lub voj voog thermal.
Solder Joint and Contact Failures
Solder joints muab qhov tseem ceeb ntawm kev sib cuag ntawm ib feem thiab ib lub voj voog thiab muaj lawv qhov ncaj ncees ntawm kev ua tsis tiav. Kev siv cov khoom siv tsis raug nrog cov khoom siv los yog PCB tuaj yeem ua rau electromigration ntawm cov khoom hauv qhov vuam. Qhov tshwm sim yog brittle txheej hu ua intermetallic txheej. Cov khaubncaws sab nraud povtseg ua rau cov pob qij txha tawg thiab feem ntau tshem tawm thaum ntxov.
Cov voj voog cua kub kuj yog qhov tseem ceeb ntawm kev sib koom ua ke tsis ua haujlwm, tshwj xeeb tshaj yog tias cov thermal expansion ntawm cov ntaub ntawv-cov khoom siv tus pin, solder, PCB kab txheej txheej, thiab PCB kab sib txawv. Raws li cov ntaub ntawv no kub thiab txias, cov neeg kho tshuab kev ntxhov siab loj heev ntawm lawv, uas tuaj yeem ua txhaum txoj kev sib txuas, ua rau cov khoom puas, lossis delaminate PCB kab.
Tin whiskers ntawm cov hlau tsis muaj hlau lead tuaj yeem ua teeb meem. Tin whiskers loj hlob tawm ntawm cov pob qij txha tsis muaj hlau lead uas tuaj yeem txuas kev sib cuag lossis tawg thiab ua rau luv.
PCB Failures
Printed circuit boards raug kev txom nyem ntau qhov chaw tsis ua haujlwm, qee qhov tshwm sim los ntawm cov txheej txheem tsim khoom thiab qee qhov los ntawm qhov chaw ua haujlwm. Thaum lub sijhawm tsim khoom, cov khaubncaws sab nraud povtseg hauv PCB lub rooj tsavxwm tuaj yeem ua tsis zoo, ua rau luv luv Circuit Court, qhib circuits, thiab hla cov teeb liab kab. Tsis tas li ntawd, cov tshuaj siv hauv PCB board etching tej zaum yuav tsis raug tshem tawm tag nrho thiab tsim cov luv luv raws li cov kab noj qab haus huv.
Siv qhov hnyav tooj liab tsis raug lossis teeb meem plating tuaj yeem ua rau muaj kev ntxhov siab ntau ntxiv uas ua rau lub neej ntawm PCB luv. Txawm hais tias cov qauv tsis ua haujlwm hauv kev tsim khoom ntawm PCB, feem ntau tsis ua haujlwm tsis tshwm sim thaum lub sijhawm tsim khoom ntawm PCB tab sis siv tom qab siv.
Qhov ib puag ncig thiab kev ua haujlwm ntawm PCB feem ntau ua rau ntau yam PCB tsis ua haujlwm dhau sijhawm. Lub tshuab hluav taws xob siv los txuas cov khoom sib txuas rau PCB tuaj yeem nyob rau ntawm qhov chaw ntawm PCB, uas yuav noj tam sim ntawd thiab corrode ib qho kev sib cuag hlau.
Solder flux tsis yog cov khoom siv corrosive nkaus xwb uas feem ntau pom nws txoj hauv kev rau PCBs vim qee cov khoom tuaj yeem xau cov kua dej uas tuaj yeem ua rau lub sijhawm. Ob peb tus neeg ua haujlwm tu tuaj yeem muaj cov txiaj ntsig zoo ib yam lossis tawm cov khoom seem, uas ua rau luv luv ntawm lub rooj tsavxwm.
Kev caij tsheb kauj vab cua sov yog lwm qhov ua rau PCB tsis ua haujlwm, uas tuaj yeem ua rau delamination ntawm PCB thiab ua lub luag haujlwm cia cov hlau fibers loj hlob nyob nruab nrab ntawm cov txheej txheem ntawm PCB.
